Conductive bonding layer with spacers between a package substrate and chip

Abstract

An embodiment related to a method for forming a device is disclosed. The method includes providing a package substrate having a first die attach pad (DAP) and a first bond pad, forming a first conductive die-substrate bonding layer on the first DAP, and attaching a first major surface of a first die to the first DAP. The first die includes a first die contact pad on a second major surface of the first die. A first conductive clip-die bonding layer with spacers is formed on the first die contact pad of the first die. A first conductive clip-substrate bonding layer is formed on the first bond pad of the package substrate. The method also includes attaching a first clip bond to the first die and the first bond pad. The first clip bond includes a first horizontal planar portion attached to the first die over the first die contact pad and a second vertical portion attached to the first bond pad.

What is claimed is: 
     
       1. A method for forming a device comprising:
 providing a package substrate having a first die attach pad (DAP) and a first bond pad; 
 forming a first conductive die-substrate bonding layer on the first DAP; 
 attaching a first major surface of a first die to the first DAP, wherein the first die includes a first die contact pad on a second major surface of the first die; 
 forming a first conductive clip-die bonding layer with spacers on the first die contact pad of the first die; 
 forming a first conductive clip-substrate bonding layer on the first bond pad of the package substrate; 
 attaching a first clip bond to the first die and the first bond pad, wherein the first clip bond includes a first horizontal planar portion attached to the first die over the first die contact pad and a second vertical portion disposed on an edge of the first horizontal planar portion and attached to the first bond pad; 
 forming a second conductive clip-die bonding layer with spacers on the first horizontal planar portion of the first clip bond; 
 attaching a first major surface of a second die to the first horizontal planar portion of the first clip bond, wherein the second die includes a second die contact pad on a second major surface of the second die; 
 forming a third conductive clip-die bonding layer with spacers on the second die contact pad of the second die; and 
 attaching a second clip bond to the second die and a second bond pad on the package substrate, wherein the second clip bond includes a first horizontal planar portion attached to the second die over the second die contact pad and a second vertical portion disposed on an edge of the first horizontal planar portion and attached to the second bond pad. 
 
     
     
       2. The method in  claim 1  wherein the first conductive clip-substrate bonding layer and the first conductive die-substrate bonding layer comprise spacers, wherein the spacers have a size equal to or smaller than a Bond Line Thickness (BLT). 
     
     
       3. The method in  claim 1  wherein the spacers comprise a material having a higher melting point than the bonding layers. 
     
     
       4. The method in  claim 1  comprises a reflow process to bond the dies and the clip bonds when the bonding layers comprise a solder paste. 
     
     
       5. The method in  claim 1  comprises a curing process to bond the dies and the clip bonds when the bonding layers comprise a sintered paste. 
     
     
       6. The method in  claim 1  comprises a reflow process and a curing process to bond the dies and the clip bonds when the bonding layers comprise a sintered paste and a solder paste. 
     
     
       7. The method in  claim 1  wherein the bonding layers are screen printed. 
     
     
       8. A method for forming a device comprising:
 providing a package substrate having a first die attach pad (DAP) and a first bond pad; 
 forming a first conductive die-substrate bonding layer on the first DAP; 
 attaching a first major surface of a first die to the first DAP, wherein the first die includes a first die contact pad on a second major surface of the first die; 
 forming a first conductive clip-die bonding layer with spacers on the first die contact pad of the first die; 
 forming a first conductive clip-substrate bonding layer on the first bond pad of the package substrate; 
 attaching a first clip bond to the first die and the first bond pad, wherein the first clip bond includes a first horizontal planar portion attached to the first die over the first die contact pad and a second vertical portion disposed on an edge of the first horizontal planar portion and attached to the first bond pad; 
 forming a second conductive die-substrate bonding layer on a second DAP on the package substrate; 
 attaching a first major surface of a second die to the second DAP, wherein the second die includes a second die contact pad on a second major surface of the second die; 
 forming a second conductive clip-die bonding layer with spacers on the second die contact pad of the second die, wherein the first horizontal planar portion of the first clip bond is attached to the second die over the second die contact pad; 
 forming a second conductive clip-substrate bonding layer on a second bond pad of the package substrate, wherein the first clip bond comprises a third vertical portion attached to the second bond pad on the package substrate, wherein the third vertical portion is disposed on an edge of the first horizontal planar portion which is oppose to the second vertical portion. 
 
     
     
       9. The method in  claim 8  wherein the spacers comprise a material having a higher melting point than the bonding layers. 
     
     
       10. The method in  claim 8  wherein the first and second conductive die-substrate bonding layers and the first and second conductive clip-substrate bonding layers comprise spacers, wherein the spacers have a size equal to or smaller than a Bond Line Thickness (BLT). 
     
     
       11. The method in  claim 8  comprises a reflow process to bond the dies and the clip bonds when the bonding layers comprise a solder paste. 
     
     
       12. The method in  claim 8  comprises a curing process to bond the dies and the clip bonds when the bonding layers comprise a sintered paste. 
     
     
       13. The method in  claim 8  comprises a reflow process and a curing process to bond the dies and the clip bonds when the bonding layers comprise a sintered paste and a solder paste. 
     
     
       14. The method in  claim 8  wherein the bonding layers are screen printed.